1. Technical Field
The invention concerns a cable, particularly a coaxial cable, with an internal conductor, an insulation which encloses the internal conductor, and an external conductor which encompasses several long elements.
2. Description of the Prior Art
Many cables comprise one or several internal conductors, an insulation which encloses the internal conductor, and an external conductor placed over it which most often forms an electrical shield. Electrical coaxial cables e.g., such as are used for antenna cables or data cables have such a construction, for instance for networking computers. An external conductor often comprises long individual elements which preferably have a nearly circular cross section, especially wires, strands or optical fibers. The elements that rest on an insulation can form a single or several independent external conductors, and essentially extend in the longitudinal direction of the cable, with a possible winding around the cable axis, or a corrugation to equalize the length. The outside of the external conductor in turn is surrounded by a cladding layer, which jointly encloses its elements and the insulation and rests against both of them. In the simplest of cases the cable jacket is the cladding layer. Especially in coaxial cables, the usual construction has a metal foil applied as the cladding layer over external conductor wires, which together form the shielding of the internal conductor or conductors.
If stiff plastic insulations are used, there is always the danger of the external conductor elements shifting during the production of the cable or its handling, particularly when the cable is bent. If the elements of the external conductor are the shield wires of a coaxial cable, the shielding can undergo considerable impairment if the shield wires of the cable are shifted to the inside of a bend. When soft insulations are used, into which the elements can penetrate, the limitation of the possible insulation materials is a disadvantage. In addition, the production requires the elements to be accurately aligned in the intended position in the cable before the cladding layer is applied. Finally it can be imagined to provide grooves in the insulation and to deposit the elements therein. However, this is also expensive and requires a high degree of production accuracy.